The present invention relates to a tire pressure monitoring system including a central unit (2, 7) with at least one trigger module (4), which is integrated into the central unit or connects through control lines (3) to the central unit, and with at least one tire module (6) arranged in a vehicle wheel (5), with the tire module being in communication with the central unit and the trigger module by means of wireless transmission technology. The tire pressure monitoring system includes fewer trigger modules than tire modules. Also, a method for the allocation of tire modules in a tire pressure monitoring system in motor vehicles, with the tire pressure monitoring system including a central unit (2, 7) with at least one trigger module (4), which is integrated into the central unit or connects through control lines (3) to the central unit, and respectively one tire module (6) per vehicle wheel (5), with the tire module being in communication with the central unit and the trigger module by means of a wireless transmission technology, wherein at least one trigger module is in communication with more than one tire module in a wireless fashion.
It is of great significance to vehicle safety to reliably monitor the tire inflation pressure on all wheels of a motor vehicle or a motorcycle. There are different approaches how to realize tire pressure monitoring systems. In the so-called directly measuring tire pressure monitoring systems, the tire inflation pressure is measured directly in the tires and is sent to an electronic evaluation unit by means of transmitting and receiving devices. A directly measuring tire pressure monitoring system of this type is e.g. described in DE 199 38 431 C2 or in DE 199 15 999 C2. Usually, the tire pressure is sensed by means of a battery-powered pressure module and is sent by radio transmission to one or more receiving modules. EP 0 806 307 B1, for example, discloses a method for implementing the allocation of the wheel position to inflation pressure checking devices in an inflation pressure checking system of a motor vehicle.
The publication DE 196 32 150 B4 describes a method of checking the inflation pressure in the tires of motor vehicle wheels. Herein, a long-wave signal is used to excite exactly one wheel electronic unit to send out a data telegram with a special identification signal, and the special identification signal is generated by a checking unit in the wheel electronic unit based on the received long-wave signal. By successive excitation of all wheel positions, the identification codes of the allocated wheel electronic units are sensed. In this arrangement, a wheel electronic unit is positioned in or at each tire, and allocated to each wheel electronic unit is a long-wave unit, which is located close by the corresponding wheel.
An object of the invention involves providing a low-cost tire pressure monitoring system, which enables a reliable allocation of tire modules to defined wheel or axle positions.